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Status of Building Code Allowances for Tall Mass Timber in the IBC

Jurisdictions that have adopted the tall mass timber code provisions in the 2021 and/or 2024 IBC International Building Code (IBC), either in whole or with local amendments

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Outdoor view mock-up of tall wood based building

Status as of September 2026

The 2021 International Building Code (IBC) and 2024 IBC are published and available from the International Code Council. These versions of the code include three new construction types—IV-A, IV-B and IV-C—that allow the use of mass timber or noncombustible materials in buildings up to 18, 12 and nine stories (respectively).  One significant change of the 2024 IBC from the 2021 IBC is related to the allowance for exposure of mass timber ceilings and integral beams in type IV-B construction. For additional information on this topic, see this WoodWorks expert tip.

The following states, or major jurisdictions therein, have adopted the tall mass timber provisions of the 2021 and/or 2024 IBC, either whole or with local amendments.    Additional local jurisdictions have adopted the mass timber provisions in advance of statewide adoption. It is recommended to check with the specific jurisdiction of the project for what requirements apply to planned construction.

  • Alabama – 2021 IBC 
  • Alaska – 2021 IBC
  • Arizona – Varies by Jurisdiction.  Many on 2024 IBC (Phoenix, Tuscon)
  • Arkansas – 2021 IBC
  • California  – 2024 IBC as part of the 2025 California Building Code
  • Colorado – Varies by Jurisdiction. Many on 2021 IBC or newer
  • Connecticut – 2021 IBC
  • Delaware – Varies by Jurisdiction.  Many on 2021 IBC or newer
  • Georgia – 2024 IBC
  • Idaho – 2021 IBC Tall Mass Timber Provisions
  • Illinois – 2024 IBC 
  • Iowa – 2024 IBC
  • Kansas – Varies by Jurisdiction.  Topeka, Wichita, and others on IBC 2021 or newer
  • Louisiana – 2021 IBC
  • Maine – 2021 IBC
  • Maryland – 2021 IBC
  • Massachusetts – 2021 IBC
  • Michigan – 2021 IBC
  • Mississippi – 2024 IBC
  • Missouri – Varies by Jurisdiction. Some on 2021 IBC. Some 2018 IBC (Kansas City)
  • Montana – 2021 IBC
  • New Hampshire – 2024 IBC
  • New Jersey – 2024 IBC
  • New Mexico – 2021 IBC
  • New York – Varies by Jurisdiction. Some on 2024 IBC
  • North Carolina – 2021 IBC
  • North Dakota – 2024 IBC
  • Ohio – 2021 IBC
  • Oklahoma – 2024 IBC
  • Oregon – 2024 IBC
  • Pennsylvania – 2021 IBC 
  • Rhode Island – 2021 IBC  
  • South Carolina – 2021 IBC 
  • South Dakota – 2021 IBC
  • Tennessee – 2021 IBC  
  • Texas – Varies by Jurisdiction. Many on 2021 IBC or newer
  • Utah – 2024 IBC
  • Vermont – 2021 IBC 
  • Virginia – 2021 IBC
  • Washington – 2024  IBC Tall Mass Timber Provisions
  • Wisconsin – 2021 IBC
  • Wyoming – 2024 IBC

For more information on the code changes, including design implications of the new construction types, see this WoodWorks paper. Additional resources can be found on our Tall Mass Timber page.

For free project assistance related to the design of tall mass timber projects, or for general education related to the tall mass timber-related code changes, contact the WoodWorks Regional Director local to you.

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